OpenCV useOpenVX_0

This node has no inputs, no optional parameters, and exactly one output: a BOOLEAN that tells you whether OpenVX acceleration is enabled in your OpenCV build. That's the whole job. It's a read-only probe for a hardware optimization layer that most ComfyUI users will never touch, which makes it one of the pack's most honest examples of "auto-generated from OpenCV's stubs, whether it's useful or not."

How it works

OpenVX is Khronos' cross-platform vision acceleration API - think "let your GPU/DSP/ISP vendor's drivers run your image kernels instead of OpenCV's own loops." OpenCV can be built against it, and when it is, cv2.useOpenVX() reports whether the runtime flag is on, and cv2.setUseOpenVX(flag) flips it. The kicker: the opencv-contrib-python wheels this pack installs are not built with OpenVX support. So on a stock install this node returns False, period, and the matching setUseOpenVX_0 node in the same pack is a no-op. You'd only ever see True on a hand-built OpenCV from source with an OpenVX implementation available.

Inputs and outputs

That's the whole schema:

• Inputs: none.
• Output: bool - True if OpenVX acceleration is active, False otherwise.

Do you actually need it?

No. This is the node you wire into nothing. If you're troubleshooting performance, useOptimized_0 (the SIMD status flag) is a marginally more relevant probe, and even that is mostly informational. If OpenVX ever matters to you, you'll know - because you'll have spent an afternoon compiling OpenCV from source, at which point you'll be reading the OpenVX docs, not this article.

It's worth keeping in mind what this pack is: the author generated one node per top-level cv2 function, including the handful that are status queries like this one. Most of the 600+ nodes in the pack are real operations you'll build workflows around. This one is a debugging leftover. "Expect dragons," the README warns, and a few of the dragons are just bits of OpenCV's API surface that don't translate to a node graph. useOpenVX_0 is one of them.

Installing

Same as every node in the pack - ComfyUI Manager, search "opencv-comfyui", install, restart. Or:

cd ComfyUI/custom_nodes
git clone https://github.com/geroldmeisinger/opencv-comfyui

The pack depends on opencv-contrib-python, numpy, and torch (its requirements.txt handles those). No models, no extra downloads.

When you might actually see it

Two scenarios. One: you're on a custom OpenCV build with OpenVX compiled in, and you want a runtime check that acceleration is on. Two: you're teaching someone how auto-generated packs produce junk-yet-functional nodes. If neither applies, feel free to never add this to a graph.